Pluripotent Male Germline Stem Cells from Goat Fetal Testis and Their Survival in Mouse Testis

Male germline stem cells (mGSCs) are stem cells present in male testis responsible for spermatogenesis during their whole life. Studies have shown that mGSCs can be derived in vitro and resemble embryonic stem cells (ESCs) properties both in the mouse and humans. However, little is know about these cells in domestic animals. Here we report the first successful establishment of goat GSCs derived from 2-5-month fetal testis, and developmental potential assay of these cells both in vitro and in vivo. These cells express pluripotent markers such as Oct4, Sox2, C-myc, and Tert when cultured as human ESCs conditions. Embryoid bodies (EBs) formed by goat mGSCs were induced with 2 x 10(-6) M retinoic acid (RA). Immunofluorescence analysis showed that some cells inside of the EBs were positive for meiosis marker-SCP3, STRA8, and germ cell marker-VASA, and haploid marker-FE-J1, PRM1, indicating their germ cell lineage differentiation. Some cells become elongated sperm-like cells after induction. Approximately 34.88% (30/86) embryos showed cleavage and four embryos were cultured on murine fibroblast feeder and formed small embryonic stem like colonies. However, most stalled at four-cell stage after intracytoplasmic sperm injection (ICSI) of these cells. Transplantation of DAPI labeled mGSCs into the seminiferous tubules of busulfan-treated mice, and showed that mGSCs can colonize, self-renew, and differentiate into germ cells. Thus, we have established a goat GSC cell line and these cells could be differentiated into sperm-like cells in vivo and sperms in vitro, providing a promising platform for generation of transgenic goat for production of specific humanized proteins.